Diagnostics data in the framework of railway tracks maintenance

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IOP Conference Series: Materials Science and Engineering

PAPER • OPEN ACCESS

Diagnostics data in the framework of railway tracks maintenance

To cite this article: J Šestáková and A Pultznerová 2021 IOP Conf. Ser.: Mater. Sci. Eng. 1015 012062

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XXIX R-P-S Seminar 2020

IOP Conf. Series: Materials Science and Engineering 1015 (2021) 012062

IOP Publishing doi:10.1088/1757-899X/1015/1/012062

Diagnostics data in the framework of railway tracks maintenance

J Šestáková and A Pultznerová

Department of Railway Engineering and Track Management, Faculty of Civil Engineering, University of Žilina, Univerzitná 8215/1, SK-01026 Žilina, Slovak Republic

E-mail address: [email protected]

Abstract. Determining the requirement and location and deciding on the time and sources of repair action is a difficult process, influenced by requirements on cost minimization and operational constraints. The particular sections of the railway track react differently to traffic and non-traffic loads, which implies the need to determine the format of development of structural quality indicators and decision-making is based on a large amount of technical and economic information, the interconnection of which is determined by the infrastructure manager. The decision-making process on repair work in the railway infrastructure management system is therefore based on the analysis of diagnostic data, technical, technological, environmental, and economic information, or the personal professional experience of the staff of the infrastructure manager. Understanding the causes of the structure's behaviour in this process leads to the identification of its weaknesses and the ability to predict its behaviour, which allows for timely planning and accurate targeting of adequate repair work to minimize the occurrence of structural faults.

1. Introduction

During the life cycle of the railway track, or of its components, the infrastructure manager performs a set of technical, technological, administrative and management activities, collectively referred to as

"maintenance" [1]. The objective of the realization of these activities is to maintain or achieve a state in which the railway track performs the required functions in the prescribed quality, comfort, and safety.

From the above, it follows that the maintenance system also includes all activities performed to rehabilitate the quality of the railway track, i.e. diagnostics and repair work (routine maintenance, repairs, or reconstructions) and their interaction. Rehabilitation of the quality of the railway track creates a fundamental set of processes implemented with the aim of safe and reliable operation during the operation of the structure.

The extension of the service life of the structure within the operational-rehabilitation cycle is affected by:

 adequate information (diagnostic data) on the operational quality of the structure,

 comprehensive analysis of diagnostic data suitable for determining the causes of the operational quality of the structure,

 adherence to diagnostic strategies in relation to repair activities,

 appropriately chosen and used tools for repair work activities,

 adequate material and technical support for repair work activities,

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 adherence to the recommended technological principles (complexity of activities) during the repair work activities.

2. Diagnostic data in the railway maintenance strategy

The main requirements of the infrastructure manager for diagnostics in relation to the planning and organization of repair work can be generally defined as the reduction of repair costs by introducing condition monitoring of the railway track in places where it is technically and economically possible to reduce repair activities, reduce repair costs with optimization, determining the life cycle costs used of the structures and their parts and repair activities, assisting to select the most appropriate type of repairs and to determine the optimal interval for repair work, maintaining the prescribed level of safety of railway operation. [2]

In the area of railway diagnostics, it is important to define the structures, their parts, or parameters that are decisive for maintaining the safety of railway traffic. Finding up-to-date information about them, in combination with “historical” data in the database of the results of previous diagnostic and repair activities, provides the basis for predicting the future state of the structure and for planning the future repair activities (figure 1).

Information on the quality of the railway track obtained by diagnostic methods should not be single use, only to inform about the current state of the structure. In the management of railway infrastructure, together with the history of already realized repair works, information databases are created, which allow behaviour monitoring of the structure in its history, predict the evolution of its quality and provide better conditions in time planning, financing, and repair technology.

Figure 1. Diagnostics data and subsequent repair activities flowchart [2].

Achieving the complexity of the diagnostic system is conditioned by keeping the structure of primary diagnostic data. The structure of the data of diagnostics of the track geometry and structural elements of the track panel and the expected quality of indicators quality necessary for the prediction of the development of the quality of the structure and the planning and organization of repair work is evident from figure 2, in which the diagnostic methods are marked with the number: 1 – visually common, 2 – video systems with recording, 3 – point manual, 4 – continuous manual contact, 5 – continuously under load contact, 6 – continuously under load contactless.

The primary data also includes the most precisely defined information about the position and time of measurement (optimally synchronized in GPS). For an adequate evaluation of the quality of the railway track, it is important to supplement the diagnostic data with the data shown in figure 3: on the construction of the track, the history of repair work, and on the traffic and transport characteristics of the diagnosed section.

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Figure 2. Track quality diagnostic data – geometry and structural elements of the track skeleton [4].

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Figure 3. Track quality diagnostic data – basic section data [4].

The railway infrastructure also consists of other components, the quality of which affects the results of determining the quality of the track geometry, its development, and the planning of repair work. The quality of the track geometry is also affected by the parameters and condition of the rolling stock that moves along it and the conditions by which the railway track is affected by its surroundings and weather.

Secondary diagnostic data are information on other variables of the track geometry (deficiency /I/ or excess /E/ track cant, horizontal track curvature /k/), railway substructure (ballast bed: condition description, % contamination, % material loss, presence of undesirable vegetation, substructure construction layers: geotechnical and hydro-technical parameters), types of rolling stock and state of its maintenance, contact geometry of wheelsets (contact angle, equivalent conicity /tg γe/), equipment and

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railway superstructure structures, railway subgrade structures and equipment, signalling equipment and security technology (SST) and energy and electrical engineering (EE), climatic conditions of measurements and operation of the railway track, conditions of the surroundings of the railway track, the history of detected faults and deficiencies, eventually also the history of accidents.

Prediction of the expected development of the design quality requires organizing the data collection in the structure so that the data are comparable: unified in type, location and collection conditions, where, in terms of [5], [6] and [7], repeatability and reproducibility of measurements are required.

Measurement and analysis of one set of diagnostic data allows only realization of the repair: if the value is exceeded, the repair activity is carried out, if not, it is not implemented.

With several consecutive measurements and their integrated analysis depending on time or other operational indicators, it is possible to detect quality deterioration trends that support the prediction of structural behaviour and thus the planning of structural rehabilitation before the values of diagnosed parameters reach the predetermined limit values and before faults occur.

At present, systems for continuous monitoring of selected parameters are being developed and used, thus obtaining information on the state of construction of the railway track, rolling stock, and the environment in real-time [8]. This information is combined with 'isolated' railway track interval diagnostics information, thus creating a basis for optimizing the planning and implementation of maintenance and repair activities in the predictive maintenance system. Such condition monitoring is important not only in terms of providing the information for decision-making in the predictive maintenance system but also for optimizing the activities of transport operations on the structure. Its properly evaluated information can help reduce operational reliability and safety risks, improve track performance, and reduce operating costs. As the current state is detected by real-time monitoring, the degradation of the monitored parameters and characteristics is operatively detected, and the railway infrastructure manager increases his ability to respond with adequate activities of routine maintenance and repair or reconstruction work [9].

Railway repair planning based on diagnostic data can be carried out in three ways. Manually – using the professional experience of an employee who visually evaluates data, e.g. in tables or graphs. This data can also be evaluated automatically. Some railway administrations use fully automated systems [10] to perform various optimizations, degradation modelling, and analysis to achieve optimal maintenance and repair. The latter method is less time consuming and allows a thorough analysis of all aspects and their development without the risk of human error, while manual methods, including visualization, are slow, inefficient, and affected by human error. Ensuring effective maintenance requires the continuous collection and analysis of data on the condition of maintained elements and data on financial costs incurred.

3. Models of relationships between repair work and diagnostic data

The planning and organization of repair work is influenced by the characteristics of the maintenance strategy, by which the method of using diagnostic data is determined. The results of the analysis of these data naturally affect the specification of the input information for the planning and organization of repair work, while they determine:

 location of the repair site within the construction of the railway track (railway superstructure, railway subgrade, etc.) and in the space (point, object, line),

 the method (work procedure) of organizing the repair,

 resources and characteristics of structure repair (material, people, machines, time, finances).

For effective financing, the repair work on the construction of railway tracks and structures (RTS) is carried out in coordinated (time, location) and comprehensively, including related work on SST and EE facilities.

The models of repair work activities express the relationship between the technology of the activity and the minimum range of diagnostic data from the group of primary indicators of the operational quality of the maintained section.

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Figure 4. Relationships between railway superstructure reconstruction activities and diagnostics data – track (replacement of track panels) [4]

Relationships between activity and data were defined in [4] for maintenance, repair and reconstruction works of track superstructure as follows:

 routine maintenance (activities were not assigned by identification codes),

 repair works (activities are indicated by codes 10 to 17),

 repair works of track structure and geometry (10),

 repair works of switch (or crossing) structure and geometry (11),

 repair works of track (or switch or crossing) ballast bed by ballast cleaning machine (12),

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 repair works of track (or switch or crossing) ballast bed by complete replacement with excavating (13),

 replacement of isolated rail supports in track (or switch or crossing) (14),

 continuous replacement of rail supports in track (15),

 replacement of isolated rails or welded rail in track (or switch or crossing) (16),

 reprofiling of rails in track (or switch or crossing) (17),

 reconstruction works (20 to 22)

 reconstruction of track railway superstructure by replacing of track panels (20) (figure 4),

 reconstruction of track railway superstructure by assembly of track skeleton in the track axis (21),

 reconstruction of switch (or crossing) railway superstructure (22).

4. Conclusions

The methods of diagnosing the operational quality of the railway track are different for individual railway infrastructure managers, even though the same parameters of railway infrastructure are measured and evaluated in principle, while the approaches to planning and organizing repair work are also different. In this area of activity of railway infrastructure managers, the regional, operational, technical, and economic conditions of railway administrations are even more manifested. These differences are the reason why it is not easy to create a universal or to apply a proven track repair planning system, although it is usually an open and constantly evolving system to which new technologies for the assessment and rehabilitation of operational quality are being adapted. A great influence on the maintenance systems has also been attributed to risk assessment, too. [11]

As the planning and organization of repair activities on a railway line relate several co-acting structures and structural elements of different quality and durability, it is not possible to create and use a single model for managing the activities of all types of repair work. In any case, management must be based on:

 correctly determined limit levels for repair action,

 properly implemented means for measuring and monitoring the quality of the structure, and

 reliable methods and tools for evaluating the current and predicting the future state of the structure.

Acknowledgments

This work was supported by the Ministry of Education, Science, Research and Sports of the Slovak Republic through the research project of scientific grant agency VEGA No. 1/0275/17: "Application of Numerical Methods in Defining the Change of the Geometric Position of a Track".

References

[1] Regulation No. TS 3-1 2011 Works on the railway superstructure (in Slovak) (Bratislava:

Slovak Railways – ŽSR)

[2] Esveld C 2016 Modern Railway Track. [electronic] ed 3.8 (Zaltbommel: MRT-Productions) [3] Regulation No. S 3-3 2005 Rail Defects (in Slovak) (Bratislava: Slovak Railways – ŽSR) [4] Šestáková J 2017 Diagnostics of Operational Quality of Railway Track and its Influence on

Renewal Work Planning (Habilitation thesis – in Slovak) (Žilina: University of Žilina) p 164 [5] STN EN 13848-2 2006 Railway Applications – Track – Track Geometry Quality – Part 2:

Measuring Systems – Track Recording Vehicles (Bratislava: Slovak Office of Standards, Metrology and Testing)

[6] STN EN 13848-3 2009 Railway Applications – Track – Track Geometry Quality – Part 3:

Measuring Systems – Track Construction and Maintenance Machines (Bratislava: Slovak Office of Standards, Metrology and Testing)

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[7] STN EN 13848-4 2011 Railway Applications – Track – Track Geometry Quality – Part 4:

Measuring Systems – Manual and Lightweight Devices (Bratislava: Slovak Office of Standards, Metrology and Testing)

[8] Roberts C and Goodall R M 2009 Strategies and Techniques for Safety and Performance Monitoring on Railways Proc. 7th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes (Barcelona) 42 (8) pp 746-755

[9] Al-Douri Y K, Tretten P and Karim R 2016 Improvement of Railway Performance: A Study of Swedish Railway Infrastructure J. Modern Transportation 24 (1) pp 22-37

[10] Pace P and Jovanovic S 2011 Using Measurement for Decision Support Int. Railway J. 51 (7) pp 37-39

[11] Grenčík J, Poprocký R, Galliková J and Volna P 2018 Use of risk assessment methods in maintenance for more reliable rolling stock operation [electronic] Machine modelling and simulations 1^st ed (London: Édition Diffusion Presse Sciences) pp 1-11